Electric discharge tube



Aug. 22, 1939.

O. BAIER ET AL ELECTRIC DISCHARGE TBE Filed Aug. l2, 1937 ffy, 7

Patented Aug. 22, 1939 UNITED STATES PATENT OFFICE ELECTRIC DISCHARGE TUBE Application August 12, 1937, Serial No. 158,661 In Germany August 18, 1936 2 Claims.

The invention relates to electric discharge tubes of the kind in which the vessel thereof is either wholly or in part composed of ceramic parts. More particularly the invention is con- 5 cerned with the arrangement of the leads, that is, the conductors connected to the electrode system and reaching through the Wall of the vessel.

In prior discharge tubes having a vessel of this construction these leads are arranged to extend l0 through a cover or a socket thereof and therefore are in closeproximity to each other especially if the tubes are for very high frequencies, hence being of particularly small dimensions. In such case great inter-electrode capacities arise,

also it is diicult to arrange the getter means and the tubular sealing-off extension.

These diiiculties are avoided by the invention, as will be understood from the following description, reference being had to the accompanying drawing in which Fig. 1 is a sectional view of an electron tube as provided by the invention, Fig. 2 is a sectional view showing part of the vessel thereof.

In this drawing, A denotes the anode that forms a tubular part of the vessel and may be of copper, for instance. K indicates the cathode, G a grid. Cathode and grid are provided with an insulating disc I which ts the inner diameter of the part A.

The leads 2, which in, a well known manner are connected to the heating filament I5 of the cathode and to the grid, are located in one plane which is vertical to the axis of the electrode system A, K, G. Filament' I5 is in the example here shown embedded in the cathode. Over the leads 2 ceramic sleeves 'I are inserted which are fixed thereon by glass seals 9. II denotes a getter means of any suitable type. The sleeves 'I are located in recesses 8 provided in the outer edge 40 of a ceramic cylinder 3 which forms partof the vessel. Cylinder 3 is seated in a cup-shaped extension E of part A and is here fastened by a glass seal IIJ. Appropriately the sleeves 'I project at their outer edge beyond cylinder 3, as will be seen in Fig. 1, but instead may be of circular or rectangular cross-sectional area. These sleeves are xed in the recesses 8 by glass seals I 2. Fixed to the parts 3, 'I by a glass seal I3 is a (Cl. Z-2.7.5)

ceramic cover 4 which carries a tubular piece 5 of ceramic material, held therein by a glass seal I and having the well known sealing-oit tube E of glass attached to it by melting.

The leads 2 thus are located between the '5 ceramic parts 3, 4.

The assembly K, G, I, 2, l, 9, Ii is as a whole inserted in the anode A. Insulating disc I by which the electrodes K, G are held in position, also acts to position K in the axis of the electron 10 tube, thus serving to centre the electrodes K, G in relation to electrode A.

The glass used to form the seals I2, I3 is of a. lower melting point than is the glass of which the seals 9, IIJ, I4 are made. Seals I2, I3 hence 15 need not be produced by the action of flames but may be produced in a simpler manner, that is, in a furnace.

A cap or hood I6 may be arranged on cover 4 in order to protect the glass portion 6 from 20 injury.

The arrangement here described enables the ceramic parts to be given exactly such dimensions as are necessary in order to obtain discharge tubes which are of the highest possible degree of 26 accuracy in every regard.

The invention is of course not restricted in scope to discharge tubes of the kind described but is independent of the number and shape of the electrodes. 30

What is claimed is:

1. A discharge tube having a vessel whose wall comprises separate ceramic parts, an electrode system contained in this vessel, leads connected to the electrode system and extending through 35 said wall, these leads being located in one plane normal to the axis of the electrode system, sleeves of ceramic material surrounding said leads and located in recesses provided in the edge of one of the ceramic Wall parts, and a seal in said 40 sleeves for the lead projecting therethrough.

2. A discharge tube according to claim 1, wherein the ceramic wall parts are a cylinder and a cover piece, the leads extending through between the two. 46

OTTO BAIER. ANNEMARIE KATSCH. 

